Drafting instrument



flame 26, 923. mgam C. P. L. NILANT I DRAFTING- :INSTRUMENT Filed June14; I921 Patented June 26, i923.

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near'rrne INSTRUMENT.

Application filed June 14, 1921. Serial No. 477,524.

2 0 all whom it may concern: 7

Be it known that I, Crrannns PHTLIPE LOUIS N near, a subject of theQueen of the Netherlands, residing at Haarlem, Wilhelminapark 27', theNetherlands, have invented certain new and useful Improvements inDrafting Instruments, of which the following is a specification. i

This invention relates to drafting instruments, particularly those knownas drafting machines. The devices of this type previously proposed havethe inherent disadvantage that they are quite complicated, and thereforeclumsy, expensive, and apt to develop a great deal of lost motion. Furthermore, the parts of such machines frequently extend beyond the edgeof the drawing board which creates danger of the instrument or thedrawing being. damaged by persons using or passing by the board, andwhile such instruments extend beyond the edges of the board, they arefrequently adapted to work effectively over only a small area of theboard.

The principal objects of the present invention are to provide a draftingmachine of the class described which is relatively simple, consequentlyinexpensive and not likely to get out of order; one which will beconfined to the limits of the board and yet be adapted to cover allportions of the board; to provide an improved means of attaching adrawing machine to an ordinary square or straight edge, and to provideanimproved means of obtaining exact adjustment which readily permits rapidapproximate adjustment.

One embodiment of the invention is illus trated in the accompanyingdrawings in which:

Figure 1 is a plan view of the instrument;

Figure 2 is a view partly in plan and partly in section on the line 22of Figure 4;

Figure 3 is an elevation of the instrument taken from the left of Figure1; and

Figure a is a section on the line 4-4 of Figure 1.

The instrument comprises a rigid frame 30, having a pair of arms 16, 17carrying scales of straight edges 21, 22 and which is pivoted in a base1 mounted on a runway 4. The runway is adapted to be rigidly secured toa straight edge, blade of a conventional square, or similar instrument 5by screws,

preferably made of metal.

The base 1 is preferably in the form of a 4 box or casing, as shown mostclearly in Figures 3 and 4, and carries four .wheels 3 having groovededges 2 for holding. it firmly on the runway. Rigidly, attached to theframe 30 is a pivot 6 which is, mounted in suitable hearings in thebase 1. The pivot may have a square end, and carries a knob 7 forrotating the arms 16, 17 for rapid adjustment. For fine adjustment aworm wheel 8 is rigidly attached to the pivot and meshes with a worm 9mounted in a frame 9 pivoted transversely to the axis of the worm andparallel to pivot 6 at 15. The worm has an axially extending portion 9*carrying a sleeve 10 having a flange 10 and an enlarged portion 11. Thesleeve and axial extension of the worm are non-circular in crosssection, so that the sleeve may slide along the extension but cannotrotate with respect thereto. The enlarged portion 11 of the sleevenormally extends through a hole 13 in the wall 31 of the slide 1 thuslocking the worm in engagement with the worm wheel. The portion 11terminates in a knob '12 which serves to rotate the worm and todisengage it from the worm wheel. A spring 82 bears against the wall. 31of the base and against the collar or flange 10,

thus tending to hold the sleeve constantly toward the left. The hole isconnected by aslot 13 with a similar hole 14 and when the knob is pulledout, the enlarged portion 11 comes out of the hole 18, and permits thesleeve 10 to pass through the slot 13*. The frame 9 may thus be rotatedto disengage the worm from the worm wheel, and the knob released toallow the enlarged portion of the sleeve to enter the hole 14, thus looking the worm out of engagement.

It will thus be seen that the rotation of the knob 12 effects fineadjustments of the angular position of the scales 21, 22, and that whenthe worm is disengaged from the worm wheel, the scales may be rapidlyadjusted by the knob 7.

On the front of the base or casing 1 is a cover plate 1 which is tractorscale 20. indiceslS, 19 are provided with a pro- One or more pointers orattached to the pivot 6,

and cooperate with the scale to register or I claim as new and desire tosecure by Letters Patent is:

1. In a drafting instrument in combination, a runway adapted to besecured to the blade of a conventional square, a base mounted on thrunway, a rigid member pivoted in the base, a pair of arms on themember, a pair of motion transmitting elements, one mounted on the rigidmember and theother on the base, and means for retaining said elementsout of engagement.

2. In a drafting instrument in combination, a runway adapted to besecured to the blade of a conventional square, a base mount ed on therunway, a rigid member pivoted in the base, a pair of arms on themember, a worm wheel on the member and a worm on the base, and means forretaining the worm out of engagement with the worm wheel.

3. In a drafting instrument in combination, a runway adapted to besecured to the blade of a conventional square, a base mount ed on therunway, a rigid member pivoted in the base, a pair of arms on themember, a worm wheel on the member and a worm on the base, the wormbeing pivoted transversely to its axis, and means for holding the wormpositively in engagement or positively out of engagement with the wormwheel.

a. In combination with a rotatable member, a worm wheel mounted on themember, a worm for rotating the wheel, the worm being mounted in a frameand having an axially the large portion of the sleeve in either Qextending portion, the frame being pivoted transversely to the axis ofthe worm, and a lock for the frame comprising a sleeve slidable on theworm extension, a fixed member adjacent the sleeve, a spring for lockingthe sleeve in relation to the fixed member, the sleeve being slidableagainst the spring to permit the frame to be rotated on its pivot.

5. In combination with a rotatable member, a worm wheel mounted on themember, a worm for rotating the wheel, the worm being mounted in a frameand having an axially extending portion, the frame being pivotedtransversely to the axis of the worm, and a lock for the framecomprising a fixed member having a pair of holes connected by a slot, asleeve passing through the fixed member and having a large portion and asmall portion, the small portion being slidably mounted on said axialextension, and a spring tending to retain the large portion of thesleeve in either of said holes, the sleeve being slidable against thespring to permit its small portion to be moved along the slot.

6, In combination with a rotatable mem her, a worm wheel mounted on themember, a worm for rotating the wheel, the worm being mounted in aframeand having an axially extending portion, the frame being pivotedtransversely to the axis of the worm, and a lock for the framecomprising a fixed mem ber having a pair of holes connected by a slot, asleeve passing through the fixed member and having a large portion and asmall portion, the small portion being slidably and non-rotatablymounted on said axially extending portion, a spring tending to retain ofsaid holes, the sleeve being slidable against the spring to permit itssmall portion to be moved along the slot, and a knob on the largeportion for rotating the worm.

In testimony whereof I aifix my signature.

CHARLES PHILIPE LOUIS NILANT.

